A precon is always a safe bet
Ideally you have a plan to close the game quickly if youre casting Trial of a Time Lord, and the card is something of a three-for-one if you do
The level of transparency is difficult for other printers to match so compare the card(s) in question with a known card (a common from the same set will work fine)
As a creature, an effect like this opens up synergy with cards like Woodland Bellower, Sun Titan, Panharmonicon, and clones like Phantasmal Image to reuse or duplicate the effect
That includes the likes of Splinter (who has the Partner mechanic, too), but also members of the TMNTs rogues gallery like Baxter, Fly in the Ointment, Leatherhead, Iron Gator, and, of course, Shredder, Shadow Master